Topic Author
Posts: 1405
Joined: Fri Aug 25, 2000 2:50 am

FR 738 Take Off

Sat Nov 15, 2003 9:36 pm

I sincerely don't know if it's only a Ryanair procedure, but I realized that every time the plane is at the beginning of the runway, ready to take off, the pilots add thrust to the engines, then they reduce it quite a lot, and finally they increase the power for the takeoff.

Is it a normal procedure or it's only a Ryanair procedure?

Why they do this?
Posts: 2598
Joined: Sat Jun 30, 2001 2:34 am

RE: FR 738 Take Off

Sat Nov 15, 2003 11:21 pm

I think its standard procedure with all opperators.

First you get the engines stabalized at around 40% N1, then you throttle up to the desired amount of thrust for the takoff.
Posts: 3985
Joined: Thu Jul 03, 2003 7:34 am

RE: FR 738 Take Off

Sun Nov 16, 2003 1:01 am

on airbus a/c, you need to do that to disengage taxi mode. not sure as to why you do that on boeings.
"...cannot the kingdom of salvation take me home."

RE: FR 738 Take Off

Sun Nov 16, 2003 1:27 am

The procedure to set takeoff power is basically the same in all airplanes.
After line-up on the runway, you advance the power levers to somewhat of a "higher" N1 or EPR power setting, this to "spool up" the engines, meaning by that that many bleed valves close at such a power setting.
When the engines are stabilized, and "spooled", a quick look at the numbers indicated (the flight engineer, in my old 747), the PF sets the takeoff power, from "spooled up", engines generally accelerate equally, and "adjustments" are done by our flight engineer.
At 80 kts, we put the "auto throttle" switch ON if we want to use it.
For our airplanes (we use EPR since we have JT9D-7Q engines) we set the "takeoff EPR" initially (that number is valid up to 80 kts), should the flight engineer need to "adjust" the power beyond 80 kts, he would have to use the "go around EPR" (somewhat lower number) since using straight "takeoff EPR" above 80 kts would possibly exceed the EPR limit of the engine...
Each engines are somewhat different, but the procedures are equivalent. I have flown airplanes with JT3D, JT4A, JT8D, JT9D, CF6 and CFM engines, while numbers are obviously different, the procedures remain the same.
Happy contrails  Smile
(s) Skipper
Posts: 1362
Joined: Sun Oct 01, 2000 9:10 pm

RE: FR 738 Take Off

Sun Nov 16, 2003 2:51 am

On 737 autothrotle is set to ARM position when the aircraft lined up with the centerline.Then the PF takes the controls advances the throttles to aproximetely 40 % N1.when both engines spooled up equally and stabilised you press the TO/GA then the A/T advances the thrust lever to desired N1 setting.That helps pilot to see if the engines responding normally and avoids uneven throttle movement which can cause loss of allignment with the runway centerline.
follow me on my facebook page" captain wing's journey log"
Posts: 3140
Joined: Fri Jan 21, 2000 11:51 am

RE: FR 738 Take Off

Mon Nov 17, 2003 12:43 am

the pilots add thrust to the engines, then they reduce it quite a lot,

I suspect the reduced sound you hear is the engines nearly matching RPMs at the ~40% spool up point. Any change in the CFM56 engine's RPM causes a fairly significant increase in noise compared to any stable RPM noise level. An engine noise level decrease is noticable even in the cockpit whenever I allow the engines to fully stabilize prior to advancing to T/O power --normally I don't wait for a complete stabilization, but rather just "close enough" to know they will spool up without problem(s).

FWIW, a rolling takeoff is the standard takeoff procedure at AA. As pointed out earlier, 99+% of the runways we use are a lot longer than "balanced field length."
*NO CARRIER* -- A Naval Aviator's worst nightmare!

Who is online

Users browsing this forum: mmo and 19 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos